Medical robotic system

ABSTRACT

The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissue. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient&#39;s skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.

RELATION TO PREVIOUSLY FILED APPLICATIONS

The present application is a continuation-in-part Application of U.S.Patent Application entitled "A Method and Apparatus For PerformingMinimally Invasive Cardiac Procedures" Ser. No. 08/755,063 filed on Nov.22, 1996, now U.S. Pat. No. 5,855,583 and which is acontinuation-in-part Application of U.S. Patent Application entitled "AMethod and Apparatus For Performing Minimally Invasive CardiacProcedures", which received Ser. No. 08/603,543 was filed on Feb. 20,1996, now U.S. Pat. No. 5,762,458. Both Applications are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and method for performingminimally invasive cardiac procedures. More particularly, the presentinvention relates to a robotic system and surgical instruments that maybe removably attached thereto, wherein said system aids in performingminimally invasive surgical procedures.

2. Description of Related Art

Blockage of a coronary artery may deprive the heart of the blood andoxygen required to sustain life. The blockage may be removed withmedication or by an angioplasty. For severe blockage a coronary arterybypass graft (CABG) is performed to bypass the blocked area of theartery. CABG procedures are typically performed by splitting the sternumand pulling open the chest cavity to provide access to the heart. Anincision is made in the artery adjacent to the blocked area. Theinternal mammary artery (IMA) is then severed and attached to the arteryat the point of incision. The IMA bypasses the blocked area of theartery to again provide a full flow of blood to the heart. Splitting thesternum and opening the chest cavity, commonly referred to as `opensurgery`, can create a tremendous trauma on the patient. Additionally,the cracked sternum prolongs the recovery period of the patient.

There have been attempts to perform CABG procedures without opening thechest cavity. Minimally invasive procedures are conducted by insertingsurgical instruments and an endoscope through small incision in the skinof the patient. Manipulating such instruments can be awkward,particularly when suturing a graft to an artery. It has been found thata high level of dexterity is required to accurately control theinstruments. Additionally, human hands typically have at least a minimalamount of tremor. The tremor further increases the difficulty ofperforming minimally invasive cardiac procedures.

To perform MIS, the surgeon uses special instruments. These instrumentsallow the surgeon to maneuver inside the patient. One type of instrumentthat is used in minimally invasive surgery is forceps, an instrumenthaving a tip specifically configured to grasp objects, such as needles.Because forceps and other instruments designed for minimally invasivesurgery are generally long and rigid, they fail to provide a surgeon thedexterity and precision necessary to effectively carry out manyprocedures in a minimally invasive fashion. For example, conventionalMIS forceps are not well suited for manipulating a needle during aminimally invasive procedure, such as during endoscopy. Therefore, manyMIS procedures that might be performed, have, as of yet, not beenaccomplished.

In essence, during open surgeries, the tips of the various instrumentsmay be positioned with six degrees of freedom. However, by inserting aninstrument through a small aperture, such as one made in a patient toeffectuate a minimally invasive procedure, two degrees of freedom arelost. It is this loss of freedom of movement within the surgical sitethat has substantially limited the types of MIS procedures that areperformed.

Dexterity is lacking in MIS because the instruments that are used failto provide the additional degrees of freedom that are lost when theinstrument is inserted into a patient. One problem associated with thislack of dexterity is the inability to suture when the instruments are incertain positions. As a result, surgeries that require a great deal ofsuturing within the surgical site are almost impossible to performbecause the surgical instruments to enable much of this work are notavailable.

Another problem associated with MIS is the lack of precision within thesurgical site. For procedures such as the MICABG (Minimally InvasiveCoronary Artery Bypass Graft), extremely small sutures must be emplacedin various locations proximate the heart. As such, precise motion of thetool at the tip of a surgical instrument is necessary. Currently, withhand positioned instruments, the precision necessary for such suturingis lacking.

As such, what is needed in the art is a tool and class of surgicalinstruments that may be articulated within the patient such that asurgeon has additional degrees of freedom available to more dexterouslyand precisely position the tool at the tip of the instrument, as isneeded.

Additionally, what is needed in the art is a method and mechanism thatprovides simple handle, instrument and tool changing capabilities sothat various tools may be easily and readily replaced to enable fasterprocedures to thus minimize operating room costs to the patient and tolessen the amount of time a patient is under anesthesia.

It is to the solution of the aforementioned problems to which thepresent invention is directed.

SUMMARY OF THE INVENTION

The present invention is a system for performing minimally invasivesurgical procedures, and more particularly, minimally invasive cardiacprocedures. The system includes a pair or more of surgical instrumentsthat are coupled to a pair or more of robotic arms. The system mayinclude only a single surgical instrument and a single robotic arm aswell and as is hereinbelow disclosed. The instruments have end effectorsthat can be manipulated to sever, grasp, cauterize, irradiate and suturetissue. Each robotic arm is coupled to a master handle by a controller.The robotic arms may be selectively connected to a specific masterhandle such that a surgeon may selectively control one or more of aplurality of robotic arms. The handles can be moved by the surgeon toproduce a corresponding movement of the end effectors and the surgicaltools attached thereto. The movement of the handles is scaled so thatthe end effectors have a corresponding movement that is different,typically smaller, than the movement performed by the hands of thesurgeon. This helps in removing any tremor the surgeon might have intheir hands. The scale factor is adjustable so that the surgeon cancontrol the resolution of the end effector movement. The scale factormay be effectuated via a voice recognition system, control buttons orthe like. The movement of the end effector can be controlled by an inputbutton, so that the end effector only moves when the button is depressedor toggled by the surgeon. Alternatively, the movement can be activatedvia voice control in a manner similar to the scaling factor adjustmentset out hereinbelow. The input button allows the surgeon to adjust theposition of the handles without moving the end effector, so that thehandles can be moved to a more comfortable position. The system may alsohave a robotically controlled endoscope which allows the surgeon toremotely view the surgical site. A cardiac procedure can be performed bymaking small incisions in the patient's skin and inserting theinstruments and endoscope into the patient. The surgeon manipulates thehandles and moves the end effectors to perform a cardiac procedure suchas a coronary artery bypass graft or heart valve surgery.

The present invention is additionally directed to a surgical instrumentand method of control thereof which permits the surgeon to articulatethe tip of the instrument, while retaining the function of the tool atthe tip of the instrument. As such, the instrument tip may bearticulated with two degrees of freedom, all the while the tool disposedat the tip may be used.

The robotic system generally comprises:

a robotic arm;

a coupler attached to the arm;

a surgical instrument that is held by the coupler;

a controller; and

wherein movement at the controller produces a proportional movement ofthe robotic arm and surgical instrument.

The present invention may include a surgical instrument that has anelongated rod. The elongated rod has a longitudinal axis and generallyserves as the arm of the endoscopic instrument. An articulate portion ismounted to and extends beyond the elongated rod. Alternatively, thearticulate portion may be integrally formed with the elongated rod. Thearticulate portion has a proximal portion, a pivot linkage and a distalportion. The proximal portion may include a pair of fingers. The fingersmay be orthogonal to each other and oriented radially to thelongitudinal axis of the elongated rod. For use in surgical procedures,it is generally preferable that the instrument and the majority of thecomponents therein are formed of stainless steel, plastic, or some othereasily steralizable material. Each of the fingers may have at least oneaperture formed therein to allow the passage of a pin which aids in theattachment of the pivot linkage to the proximal portion of thearticulate portion and which allows the pivot linkage to be pivotallymounted to the proximal portion. The articulate portion providesarticulation at the tip of an instrument that includes the articulateportion. More particularly, this provides additional degrees of freedomfor the tool at the tip of an instrument that includes an articulateportion.

An instrument such as that disclosed hereinbelow, when used inconjunction with the present surgical system, provides the surgeonadditional dexterity, precision, and flexibility not yet achieved inminimally invasive surgical procedures. As such, operation times may beshortened and patient trauma greatly reduced.

To provide increased precision in positioning the articulated tip asdisclosed hereinbelow, there is provided two additional degrees offreedom to the master controller. Each of the two additional degrees offreedom are mapped to each of the degrees of freedom at the instrumenttip. This is accomplished through the addition of two joints on themaster and automatic means for articulating the instrument tip inresponse to movements made at the master.

The objects and advantages of the present invention will become morereadily apparent to those ordinarily skilled in the art after reviewingthe following detailed description and drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a minimally invasive surgical system inaccordance with the present invention;

FIG. 2 is a schematic of a master of the system;

FIG. 3 is a schematic of a slave of the system;

FIG. 4 is a schematic of a control system of the system;

FIG. 5 is a schematic showing the instrument in a coordinate frame;

FIG. 6 is a schematic of the instrument moving about a pivot point;

FIG. 7 is an exploded view of an end effector in accordance with thesystem of the present invention;

FIG. 8 is a view of a master handle of the system in accordance with thepresent invention;

FIG. 8a is a side view of the master handle of the system in accordancewith the present invention;

FIGS. 9-10A-I are illustrations showing an internal mammary artery beinggrafted to a coronary artery;

FIG. 11 is a side view of a rear-loading tool driver in accordance withthe system of the present invention;

FIG. 12 is a plan view of the motor assembly of the back loading tooldriver of FIG. 11;

FIG. 13 is a side plan view of an articulable instrument in accordancewith the present invention;

FIG. 14 is a side plan view of an articulable instrument, where theinstrument tip is articulated;

FIG. 15 is an exploded view of the articulable portion of thearticulable instrument in accordance with the present invention;

FIG. 16 is a plan view of a pivot linkage in accordance with thearticulate portion of the articulable surgical instrument of the presentinvention;

FIG. 17 is a perspective view of an articulating tool driving assemblyin accordance with the present invention;

FIG. 18 is a view of a removable tool-tip in accordance with anarticulable instrument of the present invention;

FIG. 19 is a tool-tip receptacle in accordance with the presentinvention;

FIG. 20 is a cross-sectional view of an articulable instrument attachedto the articulate-translator of the present invention;

FIG. 21 is a close-up cross section view of the articulate-translator inaccordance with the present invention;

FIG. 22 is an end view of the articulate translator in accordance withthe present invention;

FIG. 23 is a cross-sectional view of the sterile section of thearticulating tool driving assembly in accordance with the system of thepresent invention;

FIG. 24 is a cross sectional view of the tool driver of the articulatingtool driving assembly in accordance with the system of the presentinvention;

FIG. 25 is an schematic of a master of a system in accordance with thepresent invention that includes the articulating tool driving assembly;

FIG. 26 is a plan view of a drape for use with the robotic arm inaccordance with the present invention;

FIG. 27 is a plan view of a surgical instrument having a stapling tooldisposed at the end thereof and wherein the surgical instrument isattached to the robotic arm in accordance with the present invention;

FIG. 28 is a plan view of a surgical instrument having a cutting bladedisposed at the end thereof wherein the instrument is attached to therobotic arm in accordance with the present invention;

FIG. 29 is a plan view of a surgical instrument having acoagulating/cutting device disposed at the end thereof, the instrumentattached to a robotic arm in accordance with the present invention;

FIG. 30 is a plan view of a surgical instrument having a suturing tooldisposed at the end thereof and wherein the surgical instrument isattached to the robotic arm in accordance with the present invention;

FIG. 31 is a plan view of an alternative master-handle console inaccordance the present invention;

FIG. 32 is a plan view of an alternative master-handle console inaccordance with the present invention;

FIG. 33 is a partial cut away cross-section of the master handle consolein accordance with the present invention;

FIG. 34 is a partial cut-away plan view of a handle in accordance withthe present invention;

FIG. 35 is a perspective view of an alternative embodiment of a handlein accordance with the present invention;

FIG. 36 is a top plan cross-sectional view of the handle depicted inFIG. 35;

FIG. 37 is an alternative embodiment of a handle in accordance with thepresent invention;

FIG. 38 is an alternative embodiment of a handle in accordance with thepresent invention; and

FIG. 39 is an alternative embodiment of a handle in accordance with thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings more particularly by reference numbers, FIG. 1shows a system 10 that can be used to perform minimally invasivesurgery. In a preferred embodiment, the system 10 may be used to performa minimally invasive coronary artery bypass graft, or Endoscopiccoronary artery bypass graft (E-CABG) and other anastomostic procedures.Although a MI-CABG procedure is shown and described, it is to beunderstood that the system may be used for other surgical procedures.For example, the system can be used to suture any pair of vessels aswell as cauterizing, cutting, and radiating structures within a patient.

The system 10 is used to perform a procedure on a patient 12 that istypically lying on an operating table 14. Mounted to the operating table14 is a first articulate arm 16, a second articulate arm 18 and a thirdarticulate arm 20. The articulate arms 16-20 are preferably mounted tothe table so that the arms are in a plane proximate the patient. It isto be appreciated that the arms may be mounted to a cart or some otherdevice that places the arms proximate the plane of the patient as well.Although three articulate arms are shown and described, it is to beunderstood that the system may have any number of arms, such as one ormore arms.

The first and second articulate arms 16 and 18 each have a base housing25 and a robotic arm assembly 26 extending from the base housing 25.Surgical instruments 22 and 24 are preferably removably coupled at theend of each robotic arm assembly 26 of the first and second articulatearms 16, 18. Each of the instruments 22, 24 may be coupled to acorresponding robotic arm assembly 26 in a variety of fashions whichwill be discussed in further detail hereinbelow.

The third articulate arm 20 additionally comprises a base housing 25 anda robotic arm assembly 26, and preferably has an endoscope 28 that isattached to the robotic arm assembly 26. The base housing 25 and roboticarm assemblies 26 of each of the articulate arms 16, 18, and 20 aresubstantially similar. However, it is to be appreciated that theconfiguration of the third articulate arm 20, may be different as thepurpose of the third articulate arm is to hold and position theendoscope 28 as opposed to hold and position a surgical instrument.Additionally, a fourth arm 29 may be included in the system 10. Thefourth arm 29 may hold an additional instrument 31 for purposes set outhereinbelow.

The instruments 22, 24 and 29 and endoscope 28 are inserted throughincisions cut into the skin of the patient 12. The endoscope 28 has acamera 30 that is coupled to a monitor 32 which displays images of theinternal organs of the patient 12.

Each robotic arm assembly 26 has a base motor 34 which moves the armassembly 26 in a linear fashion, relative to the base housing 25, asindicated by arrows Q. Each robotic arm assembly 26 also includes afirst rotary motor 36 and a second rotary motor 38. Each of the roboticarm assemblies 26 also have a pair of passive joints 40 and 42. Thepassive joints 40, 42 are preferably disposed orthogonal to each otherto provide pivotal movement of the instrument 22, 24 or endoscope 28that is attached to a corresponding robotic arm assembly 26. The passivejoints may be spring biased in any specific direction, however, they arenot actively motor driven. The joint angle is controlled to a particularvalue using a feedback control loop. The robotic arm assemblies 26 alsohave a coupling mechanism 45 to couple the instruments 22 and 24, orendoscope 28 thereto. Additionally, each of the robotic arm assemblies26 has a motor driven worm gear 44 to rotate the instrument 22, 24 orendoscope 28 attached thereto about its longitudinal axis. Moreparticularly, the motor driven worm gear spins the instruments orendoscope.

The first, second, and third articulate arms 16, 18, 20 as well as thefourth arm 29 are coupled to a controller 46 which can control themovement of the arms. The arms are coupled to the controller 46 viawiring, cabling, or via a transmitter/receiver system such that controlsignals may be passed form the controller 46 to each of the articulatearms 16, 18, and 20. It is preferable, to ensure error freecommunication between each of the articulate arms 16, 18, 20 and 29 andthe controller 46 that each arm 16, 18, 20 and 29 be electricallyconnected to the controller, and for the purposes of example, each arm16, 18, 20 and 29 is electrically connected to the controller 46 viaelectrical cabling 47. However, it is possible to control each of thearms 16, 18, 20 and 29 remotely utilizing well-known remote controlsystems as opposed to direct electrical connections. As such remotecontrol systems are well-known in the art, they will not be furtherdiscussed herein.

The controller 46 is connected to an input device 48 such as a footpedal, hand controller, or voice recognition unit. For purposes ofexample, a foot controller and voice recognition unit are disclosedherein. The input device 48 can be operated by a surgeon to move thelocation of the endoscope 28 and view a different portion of the patientby depressing a corresponding button(s) disposed on the input device 48.Alternatively, the endoscope 28 may be positioned via voice control.Essentially, a vocabulary of instructions to move the endoscope, such asup, down, back, and in may be recognized via a speech recognition systemand the appropriate instructions are sent to the controller. The speechrecognition system may be any well-known speech recognition software.Additionally, the controller 46 includes a vocabulary of appropriatewords that may be used with the system 10. Including such a vocabularyin the controller 46 may be accomplished through the inclusion of theaforementioned speech recognition software. To effectuate the voicerecognition a microphone 37 is included in the system 10. The microphone37 may be part of a digital system such that integrity of the signal isensure.

The controller 46 receives the input signals from the input device 48and moves the endoscope 28 and robotic arm assembly 26 of the thirdarticulate arm 20 in accordance with the input commands of the surgeon.Each of the robotic arm assemblies 26 may be devices that are sold bythe assignee of the present invention, Computer Motion, Inc. of Goleta,Calif., under the trademark AESOP. The system is also described in U.S.Pat. No. 5,515,478, which is hereby incorporated by reference. Althougha foot pedal 49 is shown and described, it is to be understood that thesystem may have other input means such as a hand controller, or a speechrecognition interface.

The movement and positioning of instruments 22, 24 attached to the firstand second articulate arms 16 and 18 is controlled by a surgeon at apair of master handles 50 and 52. Each of the master handles 50, 52which can be manipulated by the surgeon, has a master-slave relationshipwith a corresponding one of the articulate arms 16, 18 so that movementof a handle 50 or 52 produces a corresponding movement of the surgicalinstrument 22, 24 attached to the articulate arm 16, 18. Additionally, aswitch 51 may be included in the system 10. The switch 51 may be used bythe surgeon to allow positioning of the fourth arm 29. This isaccomplished because the position of the switch 51 allows the surgeon toselect which of the arms a specific handle 50 or 52 controls. In thisway, a pair of handles 50 and 52 may be used to control a plurality ofrobotic arms. The switch 51 may be connected to a multiplexer to act asa selector so that output from the multiplexer is transmitted to theappropriate robotic arm. Alternatively, the switch may have severalpositions and may, therefore, direct its output to the appropriate inputon the controller 46.

The handles 50 and 52 may be mounted to a portable cabinet 54. A secondtelevision monitor 56 may be placed onto the cabinet 54 and coupled tothe endoscope 28 via well-known means so that the surgeon can readilyview the internal organs of the patient 12. The handles 50 and 52 arealso coupled to the controller 46. The controller 46 receives inputsignals from the handles 50 and 52, computes a corresponding movement ofthe surgical instruments, and provides output signals to move therobotic arm assemblies 26 and instruments 22, 24. Because the surgeonmay control the movement and orientation of the instruments 22, 24without actually holding the ends of the instruments, the surgeon mayuse the system 10 of the present invention both seated or standing. Oneadvantage of the present system is that a surgeon may perform endoscopicsurgeries in a sitting position. This helps reduce surgeon fatigue andmay improve performance and outcomes in the operating room, especiallyduring those procedures that are many hours in length. To accommodate aseated position, a chair 57 may be provided with the system.

Alternatively, and as depicted in FIGS. 31-33, the handles 50 and 52 maybe mounted to a handle stand 900. The handle stand 900 essentiallyprovides for adjustment of the height and tilt of the handles 50 and 52.The handle stand 900 includes a base 902, a neck 904 and a handleportion 906. The base 902 may be adjusted so that the handle stand 900is tilted. A lever 908 connected to an elongated rod 910 may provide ameans for tilting the handle stand 900. As such, the stand 900 may betilted such that a surgeon using the system 10 can remain comfortablestanding or sitting while manipulating the handles 50 and 52.

Additionally, the handle stand 900 may be heightened or shorteneddepending upon the position of the surgeon (i.e. standing or sitting).This is accomplished via a telescoping section 912. The telescopingsection 912 includes an upper portion 914 telescopingly housed within alower portion 916. A spring biased detent 918 is attached to the upperportion 914 and a plurality of apertures 920 are provided in the lowerportion 916 such that the detent 918 seats in an associated aperture920. The upper portion 914 may be extended by depressing the detent 918and pulling up on the stand 900. Alternatively, the stand 900 may belowered by depressing the detent and pushing down on the stand 900. Thetelescoping section 912 and associated mechanisms serve as a means toraise and lower the stand 900.

Additionally, and as depicted in FIGS. 31-33, the handles 50 and 52 maybe attached to the stand 900 via a plurality of rollers 930 and anelongated rod 932. Motion of the rod 932 is transmitted to a pluralityof gears 934 disposed on the stand 900. The gears 934 may be housedwithin a housing 936 to protect them from the environment and topreclude access thereto. Additionally, potentiometers 938 are utilizedto measure the position of the handles 50 and 52 relative to a startingposition. This will be discussed in more detail hereinbelow. It is to beappreciated that the present invention may be accomplished eitherutilizing a cabinet 54 or a stand 900. As the handles 50 and 52 areconnected to the controller 46 in either case.

Each handle has multiple degrees of freedom provided by the variousjoints Jm1-Jm5 depicted in FIG. 2. Joints Jm1 and Jm2 allow the handleto rotate about a pivot point in the cabinet 54 or on the stand 900.Joint Jm3 allows the surgeon to move the handle into and out of thecabinet 54 in a linear manner or in a similar manner on the stand 900.Joint Jm4 allows the surgeon to rotate the master handle about alongitudinal axis of the handle. The joint Jm5 allows a surgeon to openand close a gripper.

Each joint Jm1-Jm5 has one or more position sensors which providesfeedback signals that correspond to the relative position of the handle.The position sensors may be potentiometers, or any other feedback devicesuch as rotary optical encoders that provides an electrical signal whichcorresponds to a change of position. Additionally, a plurality ofposition sensors may be emplaced at each joint to provide redundancy inthe system which can be used to alert a surgeon of malfunctions orimproper positioning of a corresponding robotic arm assembly 26.

In addition to position sensors, each joint may include tachometers,accelerometers, and force sensing load cells, each of which may provideelectrical signals relating to velocity, acceleration and force beingapplied at a respective joint. Additionally, actuators may be includedat each joint to reflect force feed back received at a robotic armassembly 26. This may be especially helpful at joint jm5 to indicate theforce encountered inside a patient by the gripper disposed at the end ofone of the tools 22, or 24. As such, a force reflective element must beincluded at the gripper of the instrument 22, 24 to effectuate such aforce reflective feedback loop. Force reflective elements, such as apiezoelectric element in combination with a whetstone bridge arewell-known in the art. However, it is not heretofore know to utilizesuch force reflection with such a system 10.

FIG. 3 shows the various degrees of freedom of each articulate arm 16and 18. The joints Js1, Js2 and Js3 correspond to the axes of movementof the base motor 34 and rotary motors 36, 38 of the robotic armassemblies 26, respectively. The joints Js4 and Js5 correspond to thepassive joints 40 and 42 of the arms 26. The joint Js6 may be a motorwhich rotates the surgical instruments about the longitudinal axis ofthe instrument. The joint Js7 may be a pair of fingers that can open andclose. The instruments 22 and 24 move about a pivot point P located atthe incision of the patient.

FIG. 4 shows a schematic of a control system that translates a movementof a master handle into a corresponding movement of a surgicalinstrument. In accordance with the control system shown in FIG. 4, thecontroller 46 computes output signals for the articulate arms so thatthe surgical instrument moves in conjunction with the movement of thehandle. Each handle may have an input button 58 which enables theinstrument to move with the handle. When the input button 58 isdepressed the surgical instrument follows the movement of the handle.When the button 58 is released the instrument does not track themovement of the handle. In this manner the surgeon can adjust or"ratchet" the position of the handle without creating a correspondingundesirable movement of the instrument. The "ratchet" feature allows thesurgeon to continuously move the handles to more desirable positionswithout altering the positions of the arms. Additionally, because thehandles are constrained by a pivot point the ratchet feature allows thesurgeon to move the instruments beyond the dimensional limitations ofthe handles. Although an input button 58 is shown and described, it isto be understood that the surgical instrument may be activated by othermeans such as voice recognition. Using the voice recognition wouldrequire a specifically vocabulary such as "AWAKE" and "SLEEP" or someother two words having opposing meanings. Voice recognition is wellknown in general, and it is the specific use of voice recognition inthis system 10 that has substantial novelty and utility.

The input button may alternatively be latched so that movement of thecorresponding instrument toggles between active and inactive each timethe button is depressed by the surgeon.

When the surgeon moves a handle, the position sensors provide feedbacksignals M1-M5 that correspond to the movement of the joints Jm1-Jm5,respectively. The controller 46 computes the difference between the newhandle position and the original handle position in computation block 60to generate incremental position values ₋₋ M1-₋₋ M5.

The incremental position values ₋₋ M1-M5 are multiplied by scale factorsS1-S5, respectively in block 62. The scale factors are typically set atless than one so that the movement of the instrument is less than themovement of the handle. In this manner the surgeon can produce very finemovements of the instruments with relatively coarse movements of thehandles. The scale factors S1-S5 are variable so that the surgeon canvary the resolution of instrument movement. Each scale factor ispreferably individually variable so that the surgeon can more finelycontrol the instrument in certain directions. By way of example, bysetting one of the scale factors at zero the surgeon can prevent theinstrument from moving in one direction. This may be advantageous if thesurgeon does not want the surgical instrument to contact an organ orcertain tissue located in a certain direction relative to the patient.Although scale factors smaller than a unit one are described, it is tobe understood that a scale factor may be greater than one. For example,it may be desirable to spin the instrument at a greater rate than acorresponding spin of the handle.

The controller 46 adds the incremental values ₋₋ M1-₋₋ M5 to the initialjoint angles Mj1-Mj5 in adder element 64 to provide values Mr1-Mr5. Thecontroller 46 then computes desired slave vector calculations incomputation block 66 in accordance with the following equations.

    Rdx=Mr3·sin(Mr2)·cos(Mr1)+Px

    Rdy=Mr3·sin(Mr2)·sin(Mr1)+Py

    Rdz=Mr3·cos(Mr2)+Pz

    Sdr=Mr4

    Sdg=Mr5

where;

Rdx,y,z=the new desired position of the end effector of the instrument.

Sdr=the angular rotation of the instrument about the instrumentlongitudinal axis.

Sdg=the amount of movement of the instrument fingers.

Px,y,z=the position of the pivot point P.

The controller 46 then computes the movement of the robotic arm 26 incomputational block 68 in accordance with the following equations.

    Jsd1=Rdz ##EQU1##

    Jsd2=tan.sup.-1 (Rdy / Rdx)+Δ for Jsd.sub.3 ≦0

    Jsd2=tan.sup.-1 (Rdy / Rdx)-{ for Jsd.sub.3 >0 ##EQU2##

    Jsd6=Mr4

    Jsd7=Mr5

where;

Jsd1=the movement of the linear motor.

Jsd2=the movement of the first rotary motor.

Jsd3=the movement of the second rotary motor.

Jsd6=the movement of the rotational motor.

Jsd7=the movement of the gripper.

L1=the length of the linkage arm between the first rotary motor and thesecond rotary motor.

L2=the length of the linkage arm between the second rotary motor and thepassive joints.

The controller provides output signals to the motors to move the arm andinstrument in the desired location in block 70. This process is repeatedfor each movement of the handle.

The master handle will have a different spatial position relative to thesurgical instrument if the surgeon releases, or toggles, the inputbutton and moves the handle. When the input button 58 is initiallydepressed, the controller 46 computes initial joint angles Mj1-Mj5 incomputational block 72 with the following equations.

    Mj1=tan.sup.-1 (ty/tx)

    Mj2=tan.sup.-1 (d/tz)

    Mj3=D

    Mj4=Js6

    Mj5=Js7 ##EQU3## The forward kinematic values are computed in block 74 with the following equations.

    Rsx=L1·cos(Js2)+L2·cos(Js2+Js3)

    Rsy=L1·sin(Js2)+L2·sin(Js2+Js3)

    Rsz=J1

The joint angles Mj are provided to adder 64. The pivot points Px, Pyand Pz are computed in computational block 76 as follows. The pivotpoint is calculated by initially determining the original position ofthe intersection of the end effector and the instrument PO, and the unitvector Uo which has the same orientation as the instrument. The positionP(x, y, z) values can be derived from various position sensors of therobotic arm. Referring to FIG. 5 the instrument is within a firstcoordinate frame (x, y, z) which has the angles θ4 and θ5. The unitvector Uo is computed by the transformation matrix: ##EQU4##

After each movement of the end effector an angular movement of theinstrument Δθ is computed by taking the arcsin of the cross-product ofthe first and second unit vectors Uo and U1 of the instrument inaccordance with the following line equations Lo and L1.

    Δθ=arcsin (|T|)

    T=Uo×U1

where;

T=a vector which is a cross-product of unit vectors Uo and U1.

The unit vector of the new instrument position U1 is again determinedusing the position sensors and the transformation matrix describedabove. If the angle Δθ is greater than a threshold value, then a newpivot point is calculated and Uo is set to U1. As shown in FIG. 6, thefirst and second instrument orientations can be defined by the lineequations Lo and L1:

Lo:

    xo=M.sub.x o·Zo+Cxo

    yo=Myo·Zo+Cyo

L1:

    x1=Mx1·Z1+Cx1

    y1=My1·Z1+Cy1

where;

Zo=a Z coordinate along the line Lo relative to the z axis of the firstcoordinate system.

Z1=a Z coordinate along the line L1 relative to the z axis of the firstcoordinate system.

Mxo=a slope of the line Lo as a function of Zo.

Myo=a slope of the line Lo as a function of Zo.

Mx1=a slope of the line L1 as a function of Z1.

My1=a slope of the line L1 as a function of Z1.

Cxo=a constant which represents the intersection of the line Lo and thex axis of the first coordinate system.

Cyo=a constant which represents the intersection of the line Lo and they axis of the first coordinate system.

Cx1=a constant which represents the intersection of the L1 and the xaxis of the first coordinate system.

Cy1=a constant which represents the intersection of the line L1 and they axis of the first coordinate system.

The slopes are computed using the following algorithms:

Mxo=Uxo/Uzo

Myo=Uyo/Uzo

Mx1=Ux1/Uz1

My1=Uy1/Uz1

CxO=Pox-Mx1·Poz

CyO=Poy-My1·Poz

Cx1=P1x-Mx1-P1z

Cy1=P1y-My1-P1z

where;

Uo(x, y and z)=the unit vectors of the instrument in the first positionwithin the first coordinate system.

U1(x, y and z)=the unit vectors of the instrument in the second positionwithin the first coordinate system.

Po(x, y and z)=the coordinates of the intersection of the end effectorand the instrument in the first position within the first coordinatesystem.

P1(x, y and z)=the coordinates of the intersection of the end effectorand the instrument in the second position within the first coordinatesystem.

To find an approximate pivot point location, the pivot points of theinstrument in the first orientation Lo (pivot point Ro) and in thesecond orientation L1 (pivot point R1) are determined, and the distancehalf way between the two points Ro and R1 is computed and stored as thepivot point R_(ave) of the instrument. The pivot point R_(ave) isdetermined by using the cross-product vector T.

To find the points Ro and R1 the following equalities are set to definea line with the same orientation as the vector T that passes throughboth Lo and L1.

tx=Tx/Tz

ty=Ty/Tz

where;

tx=the slope of a line defined by vector T relative to the Z-x plane ofthe first coordinate system.

ty=the slope of a line defined by vector T relative to the Z-y plane ofthe first coordinate system.

Tx=the x component of the vector T.

Ty=the y component of the vector T.

Tz=the z component of the vector T.

Picking two points to determine the slopes Tx, Ty and Tz (eg. Tx=x1-xo,Ty=y1-yo and Tz=z1-z0) and substituting the line equations Lo and L1,provides a solution for the point coordinates for Ro (xo, yo, zo) and R1(x1, y1, z1) as follows.

    zo=((Mx1-tx)z1+Cx1-Cxo)/(Mxo-tx)

    z1=((Cy1-Cyo)(Mxo-tx)-(Cx1-Cxo)(Myo-ty))/ ((Myo-ty)(Mx1tx)-(My1-ty)(Mxo-tx))

    yo=Myo·zo+Cyo

    y1=My1-z1+Cy1

    xo=Mxo-zo+Cxo

    x1=Mx1·z1+Cx1

The average distance between the pivot points Rc and R1 is computed withthe following equation and stored as the pivot point of the instrument.

    R.sub.ave =((x1+xo)/ 2,(y1+yo)/2,(z1+zo)/2

The pivot point can be continually updated with the above describedalgorithm routine. Any movement of the pivot point can be compared to athreshold value and a warning signal can be issued or the robotic systemcan become disengaged if the pivot point moves beyond a set limit. Thecomparison with a set limit may be useful in determining whether thepatient is being moved, or the instrument is being manipulated outsideof the patient, situations which may result in injury to the patient orthe occupants of the operating room.

While substantial real time movement of the robotic arms is provided, itmay be appreciated that pre-planned movements may be incorporated intothe present system 10. This is most advantageous with regard to movementof the endoscope. Any type of movement may be stored in am associatedmemory of the controller so that a surgeon may define his own favoritemovements and then actuate such movement by pressing a button or viavoice control. Because the movement is taught in the present applicationas well as those patents incorporated herein by reference, no furtherdisclosure of this concept is required.

To provide feedback to the surgeon, the system 10 may include a voicefeedback unit. As such, it the robotic arms suffer any malfunction, thevoice feedback may supply a message that such error has occurred.Additionally, messages regarding instrument location, time-in-use, aswell as a host of other data may be supplied to the surgeon through thevoice feedback unit. If such a condition occurs that requires a message,the system has a set of messages stored in an associated memory, suchmessage may be encoded and saved in the memory. A speech synthesis unit89, as depicted in FIG. 1 can then vocalize the message to the surgeon.In this fashion, a surgeon can maintain sight of the operativeenvironment as opposed to looking for messages displayed on a videoscreen or the like. Speech synthesis is well known, although itsinclusion in a master-slave robotic system for minimally invasivesurgery is heretofore unknown and present novel and unobviousadvantages.

To provide feedback to the surgeon the fingers of the instruments mayhave pressure sensors that sense the reacting force provided by theobject being grasped by the end effector. Referring to FIG. 4, thecontroller 46 receives the pressure sensor signals Fs and generatescorresponding signals Cm in block 78 that are provided to an actuatorlocated within the handle. The actuator provides a correspondingpressure on the handle which is transmitted to the surgeon's hand. Thepressure feedback allows the surgeon to sense the pressure being appliedby the instrument. As an alternate embodiment, the handle may be coupledto the end effector fingers by a mechanical cable that directlytransfers the grasping force of the fingers to the hands of the surgeon.

FIG. 7 shows a preferred embodiment of an end effector 80 that may beused in the present invention. The end effector 80 includes a surgicalinstrument 82, such as those disclosed hereinabove 22, 24, that iscoupled to a front loading tool driver 84. The end effector 80 ismounted to one of the robotic arm assemblies 2-6 by coupling mechanism45. The coupling mechanism 45 includes a collar 85 that removablyattaches to a holder 86. The holder 86 includes a worm gear 87 that isdriven by a motor in the robotic arm assembly 26 to rotate the collar 85and in turn rotate the instrument 82 about its longitudinal axis. Theholder 86 includes a shaft 88 that seats into a slot in the robotic armassembly 26. The shaft 88 may be turned by the motor in the armassembly, which then rotates the worm gear 87 thus rotating the collar86 and the instrument 82. A tightening tool 89 may be employed totighten and loosen the collar about the instrument 82. Such a tooloperates like a chuck key, to tighten and loosen the collar 86.

The surgical instrument 82 has a first finger 90 that is pivotallyconnected to a second finger 91. The fingers 90, 91 can be manipulatedto hold objects such as tissue or a suturing needle. The inner surfaceof the fingers may have a texture to increase the friction and graspingability of the instrument 82. The first finger 90 is coupled to a rod 92that extends through a center channel 94 of the instrument 82. Theinstrument 82 may have an outer sleeve 96 which cooperates with a springbiased ball quick disconnect fastener 98. The quick disconnect 98 allowsinstruments other than the finger grasper to be coupled to front loadingtool driver 84. For example, the instrument 82 may be decoupled from thequick disconnect 98 and replaced by a cutting tool, a suturing tool, astapling tool adapted for use in this system, such as the staplingapparatus disclosed in U.S. Pat. No. 5,499,990 or U.S. Pat. No.5,389,103 assigned to Karlsruhe, a cutting blade, or other surgicaltools used in minimally invasive surgery. The quick disconnect 98 allowsthe surgical instruments to be interchanged without having tore-sterilize the front loading tool driver 84 each time an instrument isplugged into the tool driver 84. The operation of the front loading tooldriver 84 shall be discussed in further detail hereinbelow.

The quick disconnect 98 has a slot 100 that receives a pin 102 of thefront loading tool driver 84. The pin 102 locks the quick disconnect 98to the front loading tool driver 100. The pin 102 can be released bydepressing a spring biased lever 104. The quick disconnect 98 has apiston 106 that is attached to the tool rod 92 and in abutment with anoutput piston 108 of a load cell 110 located within the front loadingtool driver 84.

The load cell 110 is mounted to a lead screw nut 112. The lead screw nut112 is coupled to a lead screw 114 that extends from a gear box 116. Thegear box 116 is driven by a reversible motor 118 that is coupled to anencoder 120. The entire end effector 80 is rotated by the motor drivenworm gear 87.

In operation, the motor 118 of the front loading tool driver 84 receivesinput commands from the controller 46 via electrical wiring, or atransmitter/receiver system and activates, accordingly. The motor 118rotates the lead screw 114 which moves the lead screw nut 112 and loadcell 110 in a linear manner. Movement of the load cell 110 drives thecoupler piston 106 and tool rod 92, which rotate the first finger 88.The load cell 110 senses the counteractive force being applied to thefingers and provides a corresponding feedback signal to the controller46.

The front loading tool driver 84 may be covered with a sterile drape 124so that the tool driver 84 does not have to be sterilized after eachsurgical procedure. Additionally, the robotic arm assembly 26 ispreferably covered with a sterile drape 125 so that it does not have tobe sterilized either. The drapes 124, 125 serve substantially as a meansfor enclosing the front loading tool driver 84 and robotic arm assembly26. The drape 125 used to enclose the robotic arm assembly 26 isdepicted in further detail in FIG. 26. The drape 125 has a substantiallyopen end 300 wherein the robotic arm assembly 26 may be emplaced intothe drape 125. The drape 125 additionally includes a substantiallytapered enclosed end 302 that effectively separates the arm assembly 26from the operating room environment. A washer 304 having a smallaperture 306 formed therethrough allows an instrument to be coupled tothe arm assembly 26 via the coupling mechanism 45. The washer 304reinforces the drape 125 to ensure that the drape 125 does not tear asthe arm assembly 26 moves about. Essentially, the instrument cannot beenclosed in the drape 125 because it is to be inserted into the patient12. The drape 125 also includes a plurality of tape 308 having adhesive310 disposed thereon. At least one piece of tape 308 is opposedlyarranged the other pieces of tape 308 to effectuate the closing of thedrape 125 about the arm assembly 26.

FIGS. 8 and 8a show a preferred embodiment of a master handle assembly130. The master handle assembly 130 includes a master handle 132 that iscoupled to an arm 134. The master handle 132 may be coupled to the arm134 by a pin 136 that is inserted into a corresponding slot 138 in thehandle 132. The handle 132 has a control button 140 that can bedepressed by the surgeon. The control button 140 is coupled to a switch142 by a shaft 144. The control button 140 corresponds to the inputbutton 58 shown in FIG. 4, and activates the movement of the endeffector.

The master handle 132 has a first gripper 146 that is pivotallyconnected to a second stationary gripper 148. Rotation of the firstgripper 146 creates a corresponding linear movement of a handle shaft150. The handle shaft 150 moves a gripper shaft 152 that is coupled aload cell 154 by a bearing 156. The load cell 154 senses the amount ofpressure being applied thereto and provides an input signal to thecontroller 46. The controller 46 then provides an output signal to movethe fingers of the end effector.

The load cell 154 is mounted to a lead screw nut 158 that is coupled toa lead screw 160. The lead screw 160 extends from a reduction box 162that is coupled to a motor 164 which has an encoder 166. The controller46 of the system receives the feedback signal of the load cell 110 inthe end effector and provides a corresponding command signal to themotor to move the lead screw 160 and apply a pressure on the gripper sothat the surgeon receives feedback relating to the force being appliedby the end effector. In this manner the surgeon has a "feel" foroperating the end effector.

The handle is attached to a swivel housing 168 that rotates aboutbearing 170. The swivel housing 168 is coupled to a position sensor 172by a gear assembly 174. The position sensor 172 may be a potentiometerwhich provides feedback signals to the controller 46 that correspond tothe relative position of the handle. Additionally, an optical encodermay be employed for this purpose. Alternatively, both a potentiometerand an optical encoder may be used to provide redundancy in the system.The swivel movement is translated to a corresponding spin of the endeffector by the controller and robotic arm assembly. This same type ofassembly is employed in the stand 900.

The arm 134 may be coupled to a linear bearing 176 and correspondingposition sensor 178 which allow and sense linear movement of the handle.The linear movement of the handle is translated into a correspondinglinear movement of the end effector by the controller and robotic armassembly. The arm can pivot about bearings 180, and be sensed byposition sensor 182 located in a stand 184. The stand 184 can rotateabout bearing 186 which has a corresponding position sensor 188. The armrotation is translated into corresponding pivot movement of the endeffector by the controller and robotic arm assembly.

A human hand will have a natural tremor typically resonating between6-12 hertz. To eliminate tracking movement of the surgical instrumentswith the hand tremor, the system may have a filter that filters out anymovement of the handles that occurs within the tremor frequencybandwidth. Referring to FIG. 4, the filter 184 may filter analog signalsprovided by the potentiometers in a frequency range between 6-12 hertz.Alternatively, an optical encoder and digital filter may be used forthis purpose.

As shown in FIGS. 9 and 10A-J, the system is preferably used to performa cardiac procedure such as a coronary artery bypass graft (CABG). Theprocedure is performed by initially cutting three incisions in thepatient and inserting the surgical instruments 22 and 24, and theendoscope 26 through the incisions. One of the surgical instruments 22holds a suturing needle and accompanying thread when inserted into thechest cavity of the patient. If the artery is to be grafted with asecondary vessel, such as a saphenous vein, the other surgicalinstrument 24 may hold the vein while the end effector of the instrumentis inserted into the patient.

The internal mammary artery (IMA) may be severed and moved by one of theinstruments to a graft location of the coronary artery. The coronaryartery is severed to create an opening in the artery wall of a size thatcorresponds to the diameter of the IMA. The incision(s) may be performedby a cutting tool that is coupled to one of the end effectors andremotely manipulated through a master handle. The arteries are clampedto prevent a blood flow from the severed mammary and coronary arteries.The surgeon manipulates the handle to move the IMA adjacent to theopening of the coronary artery. Although grafting of the IMA is shownand described, it is to be understood that another vessel such as asevered saphaneous vein may be grafted to bypass a blockage in thecoronary artery.

Referring to FIGS. 10A-J, the surgeon moves the handle to manipulate theinstrument into driving the needle through the IMA and the coronaryartery. The surgeon then moves the surgical instrument to grab and pullthe needle through the coronary and graft artery as shown in FIG. 10B.As shown in FIG. 10C, the surgical instruments are then manipulated totie a suture at the heel of the graft artery. The needle can then beremoved from the chest cavity. As shown in FIGS. 10D-F, a new needle andthread can be inserted into the chest cavity to suture the toe of thegraft artery to the coronary artery. As shown in FIG. 10H-J, new needlescan be inserted and the surgeon manipulates the handles to createrunning sutures from the heel to the toe, and from the toe to the heel.The scaled motion of the surgical instrument allows the surgeon toaccurately move the sutures about the chest cavity. Although a specificgraft sequence has been shown and described, it is to be understood thatthe arteries can be grafted with other techniques. In general the systemof the present invention may be used to perform any minimally invasiveanastomostic procedure.

Additionally, it may be advantageous to utilize a fourth robotic arm tohold a stabilizer 75. The stabilizer may be a tube or wire or some othermedical device that may be emplaced within an artery, vein or similarstructure to stabilize such structure. Using the switch 51 tointerengage the fourth robotic arm, with a handle 50 or 52 a surgeon mayposition the stabilizer 75 into the vessel. This eases the task ofplacing a stitch through the vessel as the stabilizer 75 maintains theposition of the vessel. Once the stabilizer 75 has been placed, thesurgeon then flips the switch or like mechanism to activate the roboticarm that had been disconnected to allow for movement of the fourthrobotic arm. The stabilizer 75 should be substantially rigid and holdits shape. Additionally, the stabilizer should be formed form a materialthat is steralizable. Such material are well known in the medical arts.However, this application and configuration is heretofore unknown.

As disclosed hereinabove, the system may include a front loading tooldriver 84 which receives control signals from the controller 46 inresponse to movement of a master handle 50 or 52 and drives the tooldisposed at the end of a surgical instrument. Alternatively, a backloading tool driver 200 may be incorporated into the system 10 of thepresent invention, as depicted in FIGS. 11 and 11a. The back loadingtool driver 200 cooperates with a back loadable surgical instrument 202.The incorporation of such a back loading tool driver 200 and instrument202 expedites tool changing during procedures, as tools may be withdrawnfrom the tool driver 200 and replaced with other tools in a very simplefashion.

The back loading tool driver 200 is attached to a robotic arm assembly26 via a collar and holder as disclosed hereinabove. The back loadingtool driver includes a sheath 204 having a proximal end 206 and a distalend 208. The sheath 204 may be formed of plastic or some otherwell-known material that is used in the construction of surgicalinstruments. The sheath 204 is essentially a hollow tube that fitsthrough the collar 85 and is tightened in place by the tightening toolthat is described in more detail hereinabove.

The back loadable surgical instrument 202 has a tool end 210 and aconnecting end 212. A surgical tool 214, such as a grasper or some othertool that may be driven by a push/pull rod or cable system, or asurgical tool that does not require such a rod or cable, such as acoagulator, or harmonic scalpel is disposed at the tool end 210 of theinstrument 202.

A housing 216 is disposed at the connecting end 212 of the instrument202. The housing has a lever 218 disposed interiorly the housing 216.The lever 218 has a pivot point 220 that is established by utilizing apin passing through an associated aperture 222 in the lever. The pin maybe attached to the interior wall 224 of the housing. A push/pull cableor rod 226, that extends the length of the instrument 202 is attached tothe lever 218, such that movement of the lever 218 about the pivot point220 results in a linear movement of the cable or rod 226. Essentiallythe cable or rod 226 servers as a means 227 for actuating the tool 214at the tool end 210 of the instrument 202. The cable or rod 226 may beattached to the lever via a connection pin as well. The lever 218 has aC-shape, wherein the ends of the lever 218 protrude through twoapertures 228, 230 in the housing 216. The apertures 228, 230 arepreferably surrounded by O-rings 232 the purpose of which shall bedescribed in more detail hereinbelow.

The tool end 210 of the back loadable surgical instrument 202 isemplaced in the hollow tube of the back loading tool driver 200. Thetool 202 may be pushed through the tool driver until the tool end 210extends beyond the sheath 204. The O-rings 232 seat in associatedapertures 234, 236 in a housing 238 of the tool driver 200. The housingadditionally has an aperture 240 centrally formed therethrough, theaperture being coaxial with the interior of the hollow tube. In thisfashion, the surgical instrument 202 may be inserted into and throughthe tool driver 200. Each of the O-rings 232 snugly seats in itsassociated aperture in the housing 238 of the tool driver 200.

The housing 238 additionally includes a motor assembly 242 which isdepicted in FIG. 11a. The motor assembly 242 is attached to the housing238 and is held firmly in place therein. The motor assembly generallyincludes a motor 244 attached to a reducer 246. The motor drives a leaf248 attached at the end thereof. The leaf 248 engages the ends of thelever 218 such that rotational movement of the motor results in themovement of the lever 218 about the pivot point 220. This in turnresults in the lateral movement of the means 227 for actuating the tool214 at the tool end 210 of the instrument 202. The motor moves inresponse to movements at a control handle. Additionally, force sensors248, 250 may be attached at the ends of the leaf 248. As such, a forcefeedback system may be incorporated to sense the amount of forcenecessary to actuate the tool 214 at the tool end 210 of the instrument202. Alternatively, the motor 244 may have a force feedback device 252attached thereto, which can be used in a similar fashion.

One advantage of utilizing the back loading tool driver 200 is that thesheath 204 always remains in the patient 12. As such, the tools do nothave to be realigned, nor does the robotic arm assembly 26 whenreplacing or exchanging tools. The sheath 204 retains its positionrelative to the patient 12 whether or not a toll is placed therethrough.

The system 10 of the present invention may additionally be supplied withone or two additional degrees of freedom at the tip of an instrument.For the purposes of example, two additional degrees of freedom will bedisclosed; however it is to be appreciated that only one degree offreedom may be included as well. To provide the additional degrees offreedom, and as depicted in FIGS. 13-16, an articulable surgicalinstrument 300 may be incorporated into the present. The instrument 300may be coupled to the arm assembly 26 via a collar and holder asdisclosed hereinabove. In order to articulate the tip of the articulableinstrument 300 an articulating tool driver 500 must be employed. Thearticulating tool driver 500 shall be described in more detailhereinbelow. The master must have an additional two degrees of freedomadded thereto to proved the controls for the articulation at the tip ofthe instrument 300. FIG. 25 depicts an alternative master schematic thatincludes the two additional degrees of freedom. As disclosedhereinbelow, the two additional degrees of freedom are mapped to thearticulable portion of the instrument 300. The two additional axes atthe master are referred to as Jm6 and Jm7.

By incorporating the articulable instrument 300 and the articulatingtool driver 500 and the additional degrees of freedom at the master,difficult maneuvers may be carried out in an easier fashion.

With reference to FIGS. 13-16, the articulable instrument 300 generallyincludes an elongated rod 302, a sheath 304, and a tool 306. The toolcan be a grasper, a cutting blade, a retractor, a stitching device, orsome other well-known tool used in minimally invasive surgicalprocedures. FIGS. 27-30 show various tools that may be emplaced at thedistal end of the articulable surgical instrument 300.

The instrument 300 includes an articulable portion 301 having a proximalportion 308, a pivot linkage 310 and a distal portion 212 each of whichwill be discussed in more detail hereinbelow. Additionally, theinstrument 300 includes means 311 for articulating the articulableportion 301 of the instrument 300 with respect to the elongated rod 302.The inclusion of the articulable portion 301 provides two additionaldegrees of freedom at the instrument tip. It must also be appreciatedthat although the articulable portion 301 is described as including aproximal portion, a pivot linkage and a distal portion, there may beprovided a plurality of intermediate portions each mounted to each othervia a corresponding pivot linkage.

Disposed between and mounted to each of the respective proximal portionand distal portion and any intervening intermediate portions are pivotlinkages 310. The pivot linkage 310 interengages with the proximal anddistal portions of the articulable portion to provide articulation atthe instrument tip. Essentially, the cooperation of the proximalportion, pivot linkage and distal portion serves as a universal joint.

The elongated rod 302 is preferably hollow and formed of stainless steelor plastic or some other well-know material that is steralizable.Because the rod 302 is hollow, it encompasses and defines an interior314. The elongated rod 302 additionally has a proximal end 316 and adistal end 318. The distal end 318 of the elongated rod 302 should notbe confused with the distal portion 312 of the articulable portion 301of the instrument 300.

The proximal portion 308 of the articulable portion 301 may beintegrally formed with the elongated rod 302 or it may be attachedthereto vie welding, glue or some other means well-known to the skilledartisan. It is preferable that the proximal portion 308 be integrallyformed with the elongated rod 302 to ensure sufficient stability anddurability of the instrument 300. The proximal portion 308 of thearticulable portion 301 comprises two fingers 320, 322 each of whichhave an aperture 324, 326 formed therethrough.

A pivot linkage 310 is mounted to the proximal portion 308 via aplurality of pins 328 that each pass through an associated aperture inan adjoining finger. The pivot linkage 310 is a generally flat disk 330having a central aperture 332 passing therethrough and four apertures334, 336, 338, 340 evenly spaced at the periphery of the disk 330.Additionally pins 328 are attached to and extend from the edge 342. Thepins 328 seat in the apertures of the associated fingers to provide thearticulability of the instrument 300. Five leads 350, 352, 354, 356, 358extend interiorly the hollow shaft. On lead 350 extends down the centerand passes through the center aperture 332 in the pivot linkage 310. Two352, 354 of the five leads extend down the hollow interior of theinstrument and are attached to the pivot linkage such that lineartension on one of the leads results in rotational movement of the pivotportion 301. These two leads 352, 354 attach to the pivot linkage at twoof the apertures formed therethrough. Additionally, they attach at thoseapertures that are adjacent to the pins that pass through the fingers ofthe proximal portion 308 of the articulable portion 301 of theinstrument 300. The other two leads 356, 358 pass through the two otherapertures in the pivot linkage and attach at the distal end of thearticulable portion 301. Movement of these two leads results in movementof the articulable portion 301 that is orthogonal to the movement whenthe two other leads 352, 354 are moved.

To articulate the instrument as a part of the present system, and asdepicted in FIGS. 17-24, there is provided an articulating mechanism400. The articulating mechanism 400 generally comprises the articulatingtool driver 500, a sterile coupler 600, a translator 700 and thearticulable tool 300.

The translator is attached to the proximal end 316 of the instrument300. The instrument 300 may additionally have a removable tool 420 asshown in FIGS. 18-19. The removable tool 420 may be any tool, such as acutter 422 that is attached to an elongated rod or cable 424. At the endof the rod 246 there is disposed a flat section 428 with an aperture 430formed therethrough. The flat section 428 seats into a channel 432disposed at the end of a second cable or rod 434 that travels down theelongated shaft of the instrument 300. The second cable 434 has achannel 432 formed in the end thereof such that the flat section 428seats in the channel 432. At least one spring biased detent 436 seats inthe aperture 430 disposed through the flat section 428. This connectsthe tool 420 to the rest of the instrument 300. As such, tools may beexchanged at the tip of the instrument without having to remove theinstrument from the system 10 every time a new tool is required.

The tool 300 is attached to the translator 700 and essentially isintegrally formed therewith. The articulating mechanism 400 is attachedto the robotic arm assembly 26 via the collar 85 as is disclosedhereinabove. The collar 85 fits about the shaft 302 of the instrument300.

The translator 700 has a proximal end 702 and a distal end 704. Thedistal end 704 of the translator 700 has a cross sectional shape that issubstantially similar to the cross sectional shape of the elongated rod302 of the instrument 300. Additionally, the translator 700 has a hollowinterior 706. The center rod 350 extends through the hollow interior 706of the translator 700 and emerges at the proximal end 702 thereof. Twoof the leads 352, 354 terminate interiorly the translator at twoshoulders 708, 710 that are attached to a first hollow tube 712 throughwhich the center lead 350 extends. The first hollow tube 712 may beformed of some strong durable material such as stainless steel, steel,hard plastic or the like.

The first hollow tube 712 is mounted to a bearing 714 such that it maybe rotated. Rotation of the first hollow tube 712 results in the linearmotion of the leads 352, 254 and the articulation of the articulableportion 301 of the instrument 300 in one plane of motion.

A second hollow tube 716 has a pair of shoulders 718, 719 extendingtherefrom. Two leads 356, 358 attach to one each of the shoulders 718,719. The hollow tube 716 is disposed within a bearing assembly 720 suchthat it may be rotated. Again, rotation of the second hollow tube 716results in linear movement of the leads 356, 358 which articulates thearticulable portion 301 of the instrument 300 in a plane orthogonal theplane of motion established through the rotation of the first hollowtube. It is to be appreciated that the second hollow tube 714 radiallysurrounds the first hollow tube 712. The translator 700 additionallyincludes a quick disconnect 722 comprising a pin 724 disposed at the endof a spring biased lever 726 which provides removable attachment of thetranslator 700 to the sterile coupler 600. Both of the hollow tubes 712and 716 may have notches 750 formed therein at their ends. The notchesserve as a means 752 for interconnecting each of the tubes to thesterile coupler 600 which will be discussed in further detailhereinbelow.

The translator 700 is removably attached to the sterile coupler 600 viathe quick disconnect 722. Because the articulable tool driver 500 is noteasily sterilized, it is advantageous to include a sterile coupler 600so that instruments may be exchanged without having to sterilize thearticulable tool driver 500. Additionally, the coupler 600 provides ameans by which the translator 700 may be attached to the tool driver 500while the tool driver is enclosed in a drape 125 such as that depictedin FIG. 26. The translator 600 has a housing 610 Preferably the housingand the components of the coupler 600 are formed of some easilysteralizable mater such as stainless steel, plastics or other well-knownsterilizable materials. The housing 610 has a substantially hollowinterior 612 and open ends 614 and 616. Two hollow tubes 618 and 620 arerotatively disposed within the housing 610. To effectuate the rotationof each of the tubes 618 and 620, bearings 622 and 624 are disposedabout each of the tubes. Each of the tubes has notches 626 formed in theends thereof so effectuate the attachment of the translator 700 to thecoupler 600 at one end. And to effectuate the attachment of the coupler600 to the articulable tool driver 500 at the other end thereof.

The pin 724 on the translator may seat in a notch 628 to attach thetranslator 700 to the coupler 600. Additionally, the coupler 600 mayinclude a pin 630 attached to a spring biased pivot 632 to effectuateattachment of the coupler to the driver 500. The coupler 600additionally includes a center section 634 that slidably receives theend 351 of the center cable or rod 350. The end 351 may include a tipwith a circumferential groove 353 disposed thereabout. The tip seats ina recess 636 formed in the center section 634 and is removably locked inplace by at least one spring biased detent 638. A tip 640, which issubstantially similar to the tip containing the circumferential groove353 is disposed adjacent the recess 636 and serves to attach the cablecenter cable 350 to the articulable tool driver 500, which will bediscussed in further detail hereinbelow.

The center section 634 is intended to laterally slide within theinnermost tube 618. To effectuate such a sliding motion, a linearbearing may be disposed about the center section interiorly of theinnermost tube. Alternatively, the center section 634 may be formed of abearing material that provides smooth sliding within the innermost tube618.

The coupler 600 is removably attached to the articulable tool driver500. It is intended that the articulable tool driver be enclosed by adrape 125. The articulable tool driver 500 includes a substantiallyhollow housing 502 having a closed first end 504 and a substantiallyopen second end 504. Securely disposed interiorly the housing 502 is agripper motor 506, and a pair of wrist motors 508 and 510. Each of themotors are in electrical connection with the controller 46.Alternatively, the motors may receive signals from the controller via atransmitter/receiver system where such systems are well known. It is theapplication of such a transmitter/receiver system to the presentinvention that is new. The gripper motor 506 is attached to a load nut510 that surrounds a load screw 512. The motor 506 receives the controlsignals and turns in response thereto. The load nut 510 turns whichlaterally moves the load screw 512. The load screw 512 is attached to aload cell 514 which may be employed to measure the force required tolaterally move the cable 350 which is attached vie the coupler- 600 tothe gripper motor 506. This may be used in a force feedback system thatmay be incorporated in the system 10 of the present invention. A rod 516having a channel 518 formed at the end thereof is attached to the loadcell 514. As such, the rod 516 moves in a linear fashion. The tip 640 ofthe coupler 600 seats in the channel 518 and is removably held in placeby at least one spring biased detent or some other similar attachmentmechanism 520. Therefore, if a surgeon at a master handle actuates thegrippers, the gripper motor 506 turns, thus laterally moving the rod516, and in turn the center cable 350 which opens and closes thegrippers at the tool accordingly. Of course, the action at the tool willdepend upon the type of tool disposed thereat. For example, if astapling tool is disposed at the end of the surgical instrument 300 thena stapling action would take place.

If a master handle 50 or 52 is turned about axes J6 or J7 then one ofthe two wrist motors 510, 508 corresponding to the required motionturns. Each of the motors 508, 510 are attached to a corresponding gear522, 524. Each of the gears 522, 524 engage a corresponding slottedsection 530, 532 of an associated hollow tube 526, 528 to turn theassociated tube radially about its longitudinal axis. Each of the tubes526, 528 include notched ends 534, 536 to engage the notched ends ofcorresponding hollow tubes of the coupler 600. It is to be appreciatedthat each of the hollow tubes 526, 528, 618 and 620 are all coaxial.Additionally, bearings may be emplaced intermediate each of the tubes526 and 528 to provide easy independent rotatability of the individualtubes.

When the tubes 526, 528 are rotated, they rotate the tubes in thecoupler which rotates the tubes in the translator. This results in thearticulation at the tip of the surgical instrument 300. Moreparticularly, this results in the articulation of the articulableportion of the surgical instrument 300. Additionally, whether the frontloading tool driver, the back loading tool driver, or the articulabletool driver are employed, surgical instruments may be easily exchanged.

As such, a cutting blade 800 may be exchanged for a grasper, and agrasper may be exchanged for a stapler 810. Essentially, such a systemsimplifies the performance of minimally invasive surgical procedureswhere the procedures include the step of changing one tool for another.And because the system allows articulation at the tip of certaininstruments, the articulation mechanism may be used to articulate suchstapling, or cutting instruments that incorporate the articulableportion as disclosed hereinabove.

Additionally, the instrument may not be an articulable instrument, butthe articulating mechanism can be used to control other functions, suchas stapling. FIG. 27 depicts a stapling instrument 810 attached to therobotic arm assembly via the collar 85 and holder 86. The lead that isgenerally use for the grasping tool, may be used to effectuate thestapling mechanism. Endoscopic staplers are generally well known in theart, however, it is heretofore to known to use a stapler that isattached to a robotic arm as is disclosed herein.

Additionally, a cutting blade, such as that depicted in FIG. 28 may beemployed in the system of the present invention. The cutting blade 800is attached to the robotic arm assembly 26 via the collar 85 and holder86. The cutting blade does not require a lead such as that required bythe grasper or the stapler; however, the cutting tool, may bearticulated via the articulating mechanism that has been disclosedhereinabove.

A cauterizer or coagulator may additionally be attached to the roboticarm assembly 26 via the collar 85 and holder. Cauterizers andcoagulators are well known and the cauterizing tool may be attached atthe end of an articulable instrument as disclosed hereinabove. By usinga variety of tools in predetermined sequences, various procedures may becarried out. It is generally preferable to be able to change instrumentsbecause many procedures require such.

As disclosed hereinabove, the handles 50 and 52 allow a surgeon tocontrol the movement of the tools attached to the robotic arms. As such,the configuration of the handles 50 and 52 should provide great ease ofuse for a surgeon. FIGS. 34-39 depict various handle configurations.Additionally, the handles 50 and 52 may be selected by a surgeon from aplurality of handles 960 that are available for use by the surgeon.

A proximally open handle 962 has a proximal end 963 and a distal end965. The handle 962 has first finger portion 964 and a second fingerportion 966 pivotally attached at the distal end 965 of the handle 962.A joint 968 disposed intermediate the finger portion 964 and 966provides linear motion of an elongated rod 970 which is used to actuatethe tool tip of an instrument attached to the robotic arm. This handlemay serve as one or both of the two handles 50 and 52 of the system.

A distally open handle 972 has a proximal end 973 and a distal end 975.The handle 972 has first finger portion 974 and a second finger portion976 pivotally attached at the proximal end 973 of the handle 972. Ajoint 978 disposed intermediate the finger portion 964 and 966 provideslinear motion of an elongated rod 980 which is used to actuate the tooltip of an instrument attached to the robotic arm. This handle may serveas one or both of the two handles 50 and 52 of the system.

Such handles 962 and 972 may be interchanged through the inclusion of aninterchange mechanism 984. The interchange mechanism 984 includes abiased detent latch 986 that engages an aperture in the elongated rod932 such that the handle may be attached or removed from the rod 932.

Other handle configurations are depicted in FIGS. 37-39. And moreparticularly, each of the handles 1000, 1100, and 1200 have a pair offingerseats 1020. The major difference between each of the handles 1000,1100, and 1200 is the orientation of the fingerseats to a pivot point onthe handle. The fingerseats may be parallel, or perpendicular to theaxis S of the pivot point of the handle. Each of these configurationsmay be included as an attachable handle. As such, a surgeon may exchangehandles throughout a procedure depending upon the task to beaccomplished. A surgeon may prefer one handle for a set of tasks andanother handle for a different set of tasks. As such, the surgeon mayexchange handles during the performance of a surgical procedure toenable such tasks.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the broad invention, andthat this invention not be limited to the specific constructions andarrangements shown and described, since various other modifications mayoccur to those ordinarily skilled in the art.

What is claimed is:
 1. A medical robotic system, comprising:at least tworobotic arms; a controller having at least one handle, the controller inelectrical communication with the robotic arms wherein movement at ahandle produces a proportional movement at a corresponding robotic arm;and means for switching connections between a handle of the controllerand the robotic arms such that a single handle may control a pluralityof robotic arms.
 2. The system of claim 1 wherein the means forswitching comprises a voice recognizer.
 3. The system of claim 1 whereinthe means for switching comprises a switching device.
 4. The system ofclaim 1 further comprising at least two surgical instruments coupled tothe respective at least two robotic arms.
 5. The system of claim 4wherein each of the at least two surgical instruments comprises one ofthe following: a grasper, coagulator, and scalpel.
 6. A medical roboticsystem, comprising:at least two robotic arms; at least one handle; acontroller electrically coupled to the at least one handle and the atleast two robotic arms, said controller to protect movement of said atleast one handle, and responsive thereto, to generate one or moresignals to provide proportional movement and a corresponding roboticarm; and a switch to switch communions between said at least one handleand said at least two robotic arms such that a single handle may controla plurality of robotic arms.
 7. The system of claim 6 wherein the switchcomprises a multiplexer.
 8. The system of claim 6 further comprising atleast two surgical instrument coupled to the respective at least tworobotic arms.
 9. The system of claim 8 wherein each of the at least twosurgical instruments comprises one of the following: a grasper,coagulator, and scalpel.
 10. The system of claim 6 wherein said at leastone handle is mounted to a cabinet.
 11. The system of claim 6 whereinsaid at least one handle is mounted to a handle stand.
 12. The system ofclaim 11 wherein said handle stand adjusts a height and the of the atleast one handle.